Twelve Years Since 6.8 M Quake
Published 14th December 2016, 12:48pm
It has been twelve years since the 6.8 magnitude earthquake which occurred twenty miles south of George Town on December 14, 2004. Since then, there was a 5.9 magnitude earthquake on January 19, 2010 and a number of other small tremors associated with movement of the plates in our area. None of the aforementioned earthquakes resulted in any reports of structural damage or physical injuries.
The Cayman Islands lie close to the boundary zone of the Caribbean and North American tectonic plates. There are two types of plate boundaries in the close proximity of Cayman: a short ‘spreading centre’ located due south of George Town - where the plates are diverging or pulling apart, and a ‘transform plate boundary line’ where the plates slide past each other. Both areas are known to a generate earthquakes.
Cayman is fortunate that in general we have very strong buildings and rigorous enforcement of the planning laws. The Islands are also located at least twenty miles away from the actual plate boundary areas making it less likely that Cayman will be at the epicenter of a very large earthquake, thus reducing the likelihood of major damage. However, the risk still exists and it is still important to prepare, and to mitigate against the earthquake threat.
What to Expect in an Earthquake
During an earthquake, the ground moves like waves on the ocean. The actual movement of the ground, however, is seldom the cause of injury or death. Most injuries and deaths are caused by the collapse of structures. Injuries are commonly caused by:
o Structures collapsing, falling blocks, walls, poles, roofs, ceiling plaster, light fixtures and pictures.
o Flying glass from broken windows.
o Overturned bookcases, wall units, filing cabinets, and other heavy furniture.
o Fires from ruptured gas and electrical lines. This danger may also be aggravated by a lack of water due to broken water mains.
o Fallen power lines
o Vehicular accidents
Although earthquakes strike without warning there are many actions that can be taken to reduce their impact. It is important that some of these precautions be taken before an earthquake occurs.
Before an Earthquake
Ensure your building meets the requirements of the building code. This will help make it earthquake resistant.
You can mitigate non-structural hazards in your building:
o Bolt down water heaters and gas appliances.
o Place large and heavy objects on lower shelves.
o Securely fasten shelves, heavy furniture and filing cabinets to walls.
o Bottles, glass, china, and other breakables should be stored in cabinets with doors.
o Overhead lighting fixtures and ceiling fans should be securely anchored.
o Know where and how to shut off electricity, gas and water at main switches and valves.
o Practice earthquake drills regularly so you know what to do in an earthquake.
Have on Hand:
o Flashlights and battery operated radios in case power is cut off.
o Fire extinguishers.
o First Aid kit.
o Emergency supplies of food and water.
During an Earthquake
o Stay calm
o If you are inside, stay inside. Duck, cover and hold. Take cover under a heavy desk, table, bench, in a reinforced doorway, or a reinforced (concrete) corner. Evacuate by stairway when the shaking stops. Never use elevators to evacuate after an earthquake.
o If you are outdoors, stay outdoors. During earthquakes, many injuries occur as people are entering or leaving buildings. Move away from buildings, utility wires, glass, hanging signs and other objects which may fall and cause injury. Get to an open space, stay there until the shaking stops.
After an Earthquake
o Evacuate the building in an orderly manner as soon as the shaking stops.
o Do a head count to ascertain if anyone is missing, report missing persons to the emergency services.
o Never re-enter a building after a strong earthquake until you are informed to do so by the authorities, Facilities Manager or a Structural Engineer.
o Do not attempt to move seriously injured persons unless they are in immediate danger of further injury. Moving them could make some injuries worse.
o Check for fires or fire hazards.
o Report damage to the appropriate utility companies. Never turn on electrical switches until you are informed that it is safe to do so.
o Never use matches, lighters, or open flame until you are advised that no gas leak exists.
o Ensure that sewage lines are intact before flushing toilets.
o Do not use your telephone except for genuine emergency calls.
o Listen to the radio for damage reports and other information.
o If you are on the coast move inland or to higher ground in case there is a tsunami.
o Be prepared for additional earthquake shocks called ‘aftershocks’. Although most of these are smaller than the main shock, some may be large enough to cause additional damage and damaged buildings to collapse.
o Do not go sightseeing. Keep the street clear for emergency vehicles.
For further information please contact:
Hazard Management Cayman Islands
Fourth Floor, Government Administration Building
133 Elgin Avenue
Telephone 926-2027 or 244-3145